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PubMed2004

Sex ratio and size structure of Micropogonias furnieri (Desmarest, 1823) (Perciformes, Sciaenidae) in Sepetiba Bay, Rio de Janeiro, Brazil.

Sex ratio and size structure constitute basic information in assessing reproductive potential and estimating stock size in fish populations. One hundred fifty-one individuals of Micropogonias furnieri caught by experimental otter trawls, in three zones (inner, central, and outer) of Sepetiba Bay between October 1998 and September 1999 were examined. Males outnumbered females (1.3:1.0) in all zones but no significant differences were detected. Only in the outer zone (5.0:1.0) were male/female rates significantly different according to the chi-square test. No temporal differences were observed in sex ratio. Fish size ranged from 81 to 244 mm total length (TL) with significant differences in 155 to 185 mm TL size classes, where males predominated, and a slightly higher number of females were observed for the smaller size class (TL = 95-150 mm). Size distribution varied according to the zone, with juveniles predominating in the inner and adults in the outer zone. Spatial difference in size structure observed in this study indicates that the inner bay is a rearing ground during the first life-cycle period, and movement toward the sea occurs as fish increase in size.

Animals↗

PubMed2006

Sperm cryopreservation in oncological patients: a 14-year follow-up study.

OBJECTIVE: Oncologic treatments can destroy spermatogenic dividing cells and cause azoospermia which could be irreversible. Sperm banking is the best option to preserve male fertility after these treatments. It is easy, inexpensive, and safe. To date, few clinical data are available about large series of cancer patients. Our objective was to determine the usefulness of these preventive sperm freezing protocols. DESIGN: Prospective study. SETTING: University-affiliated private fertility center. PATIENT(S): One hundred eighty-six cancer patients who banked sperm samples at our center before surgery or chemo- or radiotherapy treatments from 1991 to 2004. INTERVENTION(S): Conjugal status, age, type of cancer, treatment, and future use (if any) of the cryopreserved sperm samples for assisted reproduction technology (ART), and cycle results were recorded, analyzed, and compared with a control group. MAIN OUTCOME MEASURE(S): Basic sperm analysis of semen samples from cancer patients prior to freezing, after thawing, and after capacitation for ART. RESULT(S): A total of 320 semen samples were frozen before antineoplasic treatment. Six months later, 27% of the males recovered normal sperm production. From all frozen samples, 8.7% were discarded; the reasons were pregnancy achievement (55%), normal sperm production (28%), and patient death (18%). Finally, 5 IUI cycles and 30 ICSI cycles were done from frozen samples, with 1 and 15 pregnancies, respectively; results were comparable with those obtained in a control group. CONCLUSION(S): A significant number of males who cryopreserved semen samples before receiving antitumoral treatments have employed them. The results obtained showed that this is the strategy of choice, aiming to preserve fertility for the future, because the cost/benefit ratio is favorable. Patients should be counseled accordingly.

Adult↗

PubMed2004

Subfertility, uterine hypoplasia, and partial progesterone resistance in mice lacking the Kruppel-like factor 9/basic transcription element-binding protein-1 (Bteb1) gene.

Progesterone receptor (PR), a ligand-activated transcription factor, is a key regulator of cellular proliferation and differentiation in reproductive tissues. The transcriptional activity of PR is influenced by co-regulatory proteins typically expressed in a tissue- and cell-specific fashion. We previously demonstrated that basic transcription element-binding protein-1 (BTEB1), a member of the Sp/Krüppel-like family of transcription factors, functionally interacts with the two PR isoforms, PR-A and PR-B, to mediate progestin sensitivity of target genes in endometrial epithelial cells in vitro. Here we report that ablation of the Bteb1 gene in female mice results in uterine hypoplasia, reduced litter size, and increased incidence of neonatal deaths in offspring. The reduced litter size is solely a maternal genotype effect and results from fewer numbers of implantation sites, rather than defects in ovulation. In the early pregnant uterus, Bteb1 expression in stromal cells temporally coincides with PR-A isoform-dependent decidual formation at the time of implantation. Expression of two implantation-specific genes, Hoxa10 and cyclin D3, was decreased in uteri of early pregnant Bteb1-null mutants, whereas that of Bteb3, a related family member, was increased, the latter possibly compensating for the loss of Bteb1. Progesterone responsiveness of several uterine genes was altered with Bteb1-null mutation. These results identify Bteb1 as a functionally relevant PR-interacting protein and suggest its selective modulation of cellular processes that are regulated by PR-A in the uterine stroma.

Animals↗

PubMed2005

Body mass index and serum 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane in nulliparous Chinese women.

BACKGROUND: Basic health indicators, such as body mass index (BMI), have been associated with serum 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane/1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDT/DDE) levels; however, both positive and inverse associations of BMI with serum DDT/DDE have been reported. Given the association of BMI with a number of outcomes, it may confound studies of DDT/DDE-associated health effects. We investigated the relationship of BMI with serum DDT/DDE accounting for other determinants of exposure among women with relatively recent environmental exposures to DDT. METHODS: Serum DDT/DDE was analyzed in 466 nonsmoking, nulliparous women recruited from Anhui province in China between 1996 and 1998 as part of a reproductive health study of textile workers. The women in the sample were born between 1963 and 1977, 8 to 21 years before China's 1984 DDT ban. We used multivariate linear regression to investigate associations of BMI, age, and birth year with serum DDT/DDE. RESULTS: Mean (SD) serum total DDT concentration was 32 ng/g (17.8 ng/g). Birth year showed an inverse relationship with serum DDT independent of age. Despite limited variability in BMI, there was a consistent inverse relationship between BMI and serum DDT. Specifically, each kg/m(2) increase in BMI was associated with a -1.34 ng/g (95% confidence interval, -2.12 to -0.56 ng/g) decrease in serum total DDT. CONCLUSIONS: There were high total DDT levels in this sample of nulliparous Chinese women relative to Western populations, birth year was more strongly associated with serum DDT than age, and BMI was inversely related to serum DDT in this study.

Adult↗

PubMed2006

Evidence of interaction network evolution by whole-genome duplications: a case study in MADS-box proteins.

Recent investigations on metazoan transcription factors (TFs) indicate that single-gene duplication events and the gain and loss of protein domains are 2 crucial factors in shaping their protein-protein interaction networks. Plant genomes, on the other hand, have a history of polyploidy and whole-genome duplications (WGDs), and thus, their study helps to understand whether WGDs have also had a significant influence on protein network evolution. Here we investigate the evolution of the interaction network in the well-studied MADS domain MIKC-type proteins, a TF family which plays an important role in both the vegetative and the reproductive phases of plant life. We combine phylogenetic reconstruction, protein domain analysis, and interaction data from different species. We show that, unlike previously analyzed interaction networks, the MIKC-type protein network displays a characteristic topology, with overall high inter-subfamily connectivity, shared interactors between paralogs, and conservation of interaction patterns across species. The evaluation of the number of MIKC-type proteins at key time points throughout the evolution of land plants in the lineage leading to Arabidopsis suggested that most duplicates were retained after each round of WGD. We provide evidence that an initial network, formed by 9-11 homodimerizing proteins interacting with each other, existed in the common ancestor of all seed plants. This basic structure has been conserved after each round of WGD, adding layers of paralogs with similar interaction patterns. We thus present the first model where we can show that a network of eukaryotic TFs has evolved via rounds of WGD. Furthermore, we found that in subfamilies in which the K domain is most diverged, the interactions with other subfamilies have been largely lost. We discuss the possibility that such a high proportion of genes were retained after each WGD because of their capacity to form higher order complexes involving proteins from different subfamilies. The simultaneous duplications allowed for the conservation of the quantitative balance between the constituents and facilitated sub- and neofunctionalization through differential expression of whole units.

Computational Biology↗

PubMed1988

The dynamics of vector-transmitted diseases in human communities.

The development of vector-transmitted disease models and their application to field studies is reviewed. The key concepts of the basic rate of reproduction and disease transmission threshold are explained, and their application to disease control briefly illustrated. The complications involved in producing appropriate models are discussed for the case of the trypanosomatid parasites Leishmania and Trypanosoma that frequently have more than one vertebrate host and are often fatal in the human host. A two-species, vector-borne disease model allows a quantification of the role of animal reservoirs in maintaining human diseases. Human prevalence may be determined more by the parasitological characteristics of wild reservoir species, about which little is generally known, than by any other single feature of the complex interaction between parasites, vectors and hosts. Domestic animals are often ideal reservoirs, maintaining large numbers of vectors and considerably enlarging the parasite pool. When vector-transmitted diseases are fatal to the human host, human and vector dynamics interact in ways which may cause epidemic cycles, low-level endemic equilibria or disease extinction. For both leishmaniasis and trypanosomiasis it is suggested that a very small number of chronic human cases can maintain the disease in the human population over long periods of time between epidemic outbreaks. They may also be important in the maintenance of geographically distinct foci, characteristic of human trypanosomiasis in Africa. Finally there is a plea to establish a tradition of field observation leading to, and being directed by, mathematical models which in turn are modified as the observations accumulate. All too often, one-way traffic between the two results in slow, or misguided, progress.

Animals↗

PubMed2000

Adolescent health and the environment.

The effects of toxicants depend on the dose and the time in the life span when exposure occurs. The biology of adolescence is distinctive and provides opportunities for unique actions of toxicants both in terms of disruption of function and disruption of maturation. Maturation of a number of organ systems occurs during this period, including not only the reproductive system but also the respiratory, skeletal, immune, and central nervous systems. Adolescence is a time of increased risk for infectious disease and accidental injury, making the effects of toxicants on the immune and central nervous systems particularly harmful. Differences in blood volume, respiratory parameters, metabolic needs, and capacity all contribute to altered pharmacokinetics. Exposures can also change. Increased food intake associated with rapid adolescent growth alters exposure to food contaminants. Voluntary drug consumption increases, including drinking; smoking; substance abuse; and the use of over-the-counter, prescription, and performance-enhancing drugs. At the same time, adolescents are introduced to toxicants in the workplace. Basic research in the toxicology of adolescence needs to take into account the appropriateness of animal models for this distinctive human developmental stage; risk assessment must take into account pharmacokinetic and lifestyle factors. Screening methodologies that would identify toxic effects unique to adolescence would also be valuable.

Adolescent↗

PubMedDate not supplied

[Correlation analysis of predictive factors of successful implantation in fertilization in vitro].

INTRODUCTION: Endometrial receptivity as isolated predictive factor of successful implantation, with its specifity is determined with numbered factors. PURPOSE: Purpose of this study was to evaluate significance and correlation between relevant factors using appropriate statistical analyses on term of embryo implantation. MATERIAL AND METHODS: Evaluated group contained 85 women whom according different causes of infertility have been determined for assisted reproduction program. Analysed measurements were: endometrial thickness, assessed hyperechogenity in relation with absolute endometrial thickness (HEA relation) and uterine blood flow (pulsatile index-Pi). Simultaneously were analyzed serum estradiol (E2; pg/ml) and progesterone (P; nmol/l) levels. After these evaluations achieved results were processed with standard statistical pack. Beside that were applied parameter and nonparameter tests with aim to test significancy of difference and multiple regressive analyse (Stepwise). RESULTS: Resulted measured parameters have been presented in basic analyse as middle value (Xrs) from all measurements + SD (standard deviation) and significance of difference is tested by mentioned statistical tests (Table 1). Application of Stepwise analyse, "step by step", has used parameter by parameter based on value which has decreased variability and based on achieved correlative coefficient between dependent uneven and complex of independent uneven values. This procedure confirms best correlation between HEA relation and serum progesterone levels and HEA relation in correlation with associated values: P, E2 and endometrial thickness (Table 1). DISCUSSION: Investigation provided till now shows that embryo quality and endometrial receptivity with highest probability determine success of applied assisted reproduction, successful embryonal implantation There is assessed influence of endometrial receptivity represented trough HEA relation using many folded regressive analyse where qualitative endometrial value has been looked with dependency with other parameters gives picture for high determinancy with hormonal activity and with stimulative ovarian activity. This determinancy could be viewed mostly through serum progesterone levels on day of HCG administration. Correlative relation between qualitative endometrial characteristics on day of HCG administration has high value related to progesterone levels. CONCLUSION: Results presented with this research confirm once again complexity characteristic for factors that play final role in embryo implantation in IVF program. There is presented only one aspect related with this problem with aim to contribute quantification importance and assessment rate of mutual influence these factors known till now as relevant.

Blood Flow Velocity↗

PubMed2000

[Polycystic ovary syndrome].

The polycystic ovary syndrome (PCOS) is the most frequent endocrine disease in women of reproductive age. Hyperandrogenism, anovulation and metabolic syndrome are the cardinal features of PCOS. Hyperandrogenism results from a diffuse enzymatic hyperactivity at the theca-interstitial cell level. Anovulation is due to an impairment of the selection of a dominant follicle, while the number of smaller follicles is exaggerated. The molecular grounds of insulin resistance could be an increased Serine phosphorylation of the insulin receptor. The clinical classification of PCOS distinguishes three forms: the classic PCOS, where the three above mentioned features are present, the non classic PCOS and the asymptomatic PCOS, revealed by ultrasonography. Only the increased ovarian volume or surface (>11ml and> 5.5cm(2), respectively) must be viewed as a specific ultrasonic sign of PCOS. Cyproterone acetate remains the basic treatment of hyperandrogenism. The treatment of anovulation and infertility follows a consensual strategy. The insulin sensitizing treatment allows to decrease hyperandrogenism, to reverse the menstrual cycle irregularity and to obtain spontaneous or induced pregnancies.

Anovulation↗

PubMed2004

Dynamics of global gene expression changes during mouse preimplantation development.

Understanding preimplantation development is important both for basic reproductive biology and for practical applications including regenerative medicine and livestock breeding. Global expression profiles revealed and characterized the distinctive patterns of maternal RNA degradation and zygotic gene activation, including two major transient waves of de novo transcription. The first wave corresponds to zygotic genome activation (ZGA); the second wave, named mid-preimplantation gene activation (MGA), precedes the dynamic morphological and functional changes from the morula to blastocyst stage. Further expression profiling of embryos treated with inhibitors of transcription, translation, and DNA replication revealed that the translation of maternal RNAs is required for the initiation of ZGA. We propose a cascade of gene activation from maternal RNA/protein sets to ZGA gene sets and thence to MGA gene sets. The large number of genes identified as involved in each phase is a first step toward analysis of the complex gene regulatory networks.

Animals↗

PubMedDate not supplied

[Relationships between basic life history parameters and population size].

We consider an ideal population with a stable age composition changing according Lotka equation. Additional assumptions are made concerning the constancy of population size, independence of specific mortality rate on age, and linear dependence of female fecundity on its weight. A relationship has been obtained [formula: see text] where N0 is initial numbers of a generation, N[alpha, omega] is total numbers of the mature part of the population, w[alpha, omega] is a mean weight of a mature individual, s is sex ratio, c is specific fecundity (per unit of weight) and l0 is the probability of larval surviving. The growth of an individual is described by the Bertalanffy function. Methods of calculation of life history parameters are discussed. A method is proposed to calculate the age of maturity (alpha) and at the end (omega) of the reproduction period as first and second inflection points of the growth rate curve. Based upon data on development of 27 populations of several species of fishes of inland waters of Russia the following relationship have been obtained: [formula: see text] for populations with [formula: see text] < or = 100 g, [formula: see text] for populations with [formula: see text] > 100 g, and [formula: see text] for all populations.

Animals↗

PubMedDate not supplied

Dynamics of human follicular growth and in-vitro oocyte maturation.

The physiological trigger for meiotic resumption in the human oocyte is the surge of luteinizing hormone, but it can also occur spontaneously if oocytes are released from antral follicles and cultured in vitro. The development of novel techniques for the culture of murine oocytes has raised the possibility of growing human oocytes to maturity in vitro. Such a system could open the door to a number of techniques with revolutionary consequences. It would clearly be of benefit in basic physiological studies of follicular development, as well as being used to test the effect of toxicological substances on oocyte maturation. More significantly, such a system could provide a source of human oocytes for in-vitro fertilization (IVF) where immature or germinal vesicle oocytes are cultured to maturity before being fertilized. If this can be achieved, it might facilitate oocyte cryopreservation, where surplus oocytes are stored, thus avoiding the need for repeated superovulation. A combination of immature oocyte cryopreservation for later maturation and IVF will provide the opportunity to establish oocyte banks and help overcome some of the practical and ethical dilemmas that are currently shadowing the field of reproductive medicine.

Animals↗

PubMed2005

Aquinas's account of human embryogenesis and recent interpretations.

In addressing bioethical issues at the beginning of human life, such as abortion, in vitro fertilization, and embryonic stem cell research, one primary concern regards establishing when a developing human embryo or fetus can be considered a person. Thomas Aquinas argues that an embryo or fetus is not a human person until its body is informed by a rational soul. Aquinas's explicit account of human embryogenesis has been generally rejected by contemporary scholars due to its dependence upon medieval biological data, which has been far surpassed by current scientific research. A number of scholars, however, have attempted to combine Aquinas's basic metaphysical account of human nature with current embryological data to develop a contemporary Thomistic account of a human person's beginning. In this article, I discuss two recent interpretations in which it is argued that a human person does not begin to exist until a fetus has developed a functioning cerebral cortex.

Beginning of Human Life↗

PubMed2003

Bovine embryo technologies.

Embryo technologies are a combination of assisted reproduction, cellular and molecular biology and genomic techniques. Their classical use in animal breeding has been to increase the number of superior genotypes but with advancement in biotechnology and genomics they have become a tool for transgenesis and genotyping. Multiple ovulation and embryo transfer (MOET) has been well established for many years and still accounts for the majority of the embryos produced worldwide. However, no progress has been made in the last 20 years to increase the number of transferable embryos and to reduce the side effects on the reproductive performance of the donors. In vitro embryo production (IVP) is a newer and more flexible approach, although it is technically more demanding and requires specific laboratory expertise and equipment that are most important for the quality of the embryos produced. Somatic cell cloning is a rapidly developing area and a very valuable technique to copy superior genotypes and to produce or copy transgenic animals. More knowledge in oocyte and embryo biology is expected to shed new light on the early developmental events, including epigenetic changes and their long lasting effect on the newborn.Embryo technologies are here to stay and their use will increase as advances in the understanding of the mechanisms governing basic biological processes are made.

Animals↗

PubMed1981

Cleavage patterns, cell lineages, and development of a cytoplasmic bridge system in Volvox embryos.

We report an extensive scanning electron microscope (SEM) study of cleavage planes, cell shape changes, and cell lineages during cleavage of the asexual embryo of Volvox carteri f. nagariensis. Although our data generally confirm the basic description of cleavage developed by others using light microscopy, there is one important exception. We observed that the fourth cleavage plane is much more oblique than had previously been recognized. We show that, as a result, the four tiers of cells in the 16-cell embryo overlap extensively, and the new generation of asexual reproductive cells, or gonidia, are derived from three of these tiers (rather than two, as previously believed). Our study focused on the development of the highly organized system of cytoplasmic bridges that appears during cleavage. Hundreds of cytoplasmic bridges are formed in each division cycle as a result of incomplete cytokinesis. Existing bridges are conserved and divided between daughter cells while new bridges are formed at each division. Hence, the number of bridges per embryo increases regularly even though the number per cell declines from the fourth cleavage on. The bridges are organized into bands that girdle the cells at a predictable level and exhibit a regular 500-nm interbridge spacing; bridge bands of adjacent cells are in register and form a structural continuum throughout the embryo which we term "The cytoplasmic bridge system." The only place where bridges are not present is along a pair of intersecting slits, called the phialopore. We describe in detail the development of this bridge-free region.

Cell Communication↗

PubMed1996

Breast cancer and environmental risk factors: epidemiological and experimental findings.

Breast cancer has long been associated with reproductive hormone exposures. Recently, greater attention has been focused on environmental exposures that may be responsible for some proportion of breast cancer incidence. Several etiologic aspects are discussed. A number of chemicals induce breast cancer in rodents--including solvents, pesticides, and polycyclic aromatic hydrocarbons--and these might serve as leads for studies in humans. In women, strong links have been established between breast cancer risk and ionizing radiation. Evidence for nonionizing radiation (electromagnetic field) exposures and breast cancer is suggestive, albeit limited. Occupational exposures have not been identified as breast cancer risks, but several associations need further study, including solvents and pesticides. Time of life when exposures take place is important, and this claim is strongly supported by data on cigarette smoking and radiation. Also, basic research has demonstrated that mammary tissue is more susceptible to carcinogenesis at certain periods of breast development. Likewise, prenatal, neonatal, and adolescent exposures deserve continuing attention. Research on etiology of breast cancer should measure environmental exposures and take into account the time of life at which these occur. Complex interactions between exogenous and endogenous carcinogenic agents need further focus, as modulated by varying genetically determined individual susceptibilities.

Animals↗

PubMed2003

Current challenges in cystic fibrosis screening.

CONTENT: This article gives an overview of the symptoms and mutations associated with classic and atypical cystic fibrosis (CF). Current testing methods for mutation detection in CF are discussed. OBJECTIVES: Review testing for CF, including American College of Medical Genetics and American College of Obstetrics and Gynecology guidelines and recommendations regarding population screening for CF. Describe symptomatic and mutational differences between patients with classic CF and atypical CF, including monosymptomatic conditions such as congenital bilateral absence of the vas deferens, idiopathic pancreatitis, and chronic sinusitis. Explain the concern about predicting the phenotypic expression of the condition from the genotype. Discuss the challenges of CF testing, including the preanalytic, analytic, and postanalytic phases. List the current methods for detecting CF transmembrane conductance regulator gene mutations, specifying the advantages and disadvantages of each. Describe the basic patient information necessary for laboratories to provide accurate risk assessments, such as ethnicity and family history, and reasons for the test being conducted (carrier or affected status). RESULTS: The technical challenges of detecting the 25 recommended mutations are being met by commercially available reagents. Challenges remain for the preanalytic and postanalytic phases. Only with accurate patient information can laboratories provide specific risk reductions on the basis of a negative genetic test result. CONCLUSION: As health care providers become better informed about the recommendations for CF testing and laboratories continue to increase the sensitivities of their assays, patients will benefit from increased screening efficiency and accuracy. This will allow affected individuals to receive prompt and effective treatment and carriers to enjoy an expanded number of reproductive options.

Algorithms↗

PubMedDate not supplied

Bio-inspired computing tissues: towards machines that evolve, grow, and learn.

Biological inspiration in the design of computing machines could allow the creation of new machines with promising characteristics such as fault-tolerance, self-replication or cloning, reproduction, evolution, adaptation and learning, and growth. The aim of this paper is to introduce bio-inspired computing tissues that might constitute a key concept for the implementation of 'living' machines. We first present a general overview of bio-inspired systems and the POE model that classifies bio-inspired machines along three axes. The Embryonics project--inspired by some of the basic processes of molecular biology--is described by means of the BioWatch application, a fault-tolerant and self-repairable watch. The main characteristics of the Embryonics project are the multicellular organization, the cellular differentiation, and the self-repair capabilities. The BioWall is intended as a reconfigurable computing tissue, capable of interacting with its environment by means of a large number of touch-sensitive elements coupled with a color display. For illustrative purposes, a large-scale implementation of the BioWatch on the BioWall's computational tissue is presented. We conclude the paper with a description of bio-inspired computing tissues and POEtic machines.

Cell Differentiation↗